Magnet for telegraphones.



No. 889,317. PATENTED JUNE 2, 1908. J. A. LIEB. MAGNET FOR TELEGRAPHONES.

APPLICATION FILED MAR. 26, 1907- 19 it m am c J .15 raphone, to which my N TE STATE PATENT OFFICE. 1

JOHN A. LIEB, OF NEW YORK, N. Y., ASSIGNOR TO AMERICAN TELEGRAIHONE COMPANY,

' A CORPORATION OF THE DISTRICT OF COLUMBIA.

MAGNET FOR TELEGRAPHONES.

Specification r Letters Patent.

Patented June 2, 1908.

Application filed March 25, 1907. Serial No. 864,510.

To all whom it may concern:

Be it known that I, JOIIN'A. LIEB, a citizen of the United States, residing at the city of New York, in the borough of Brooklyn 5 and StateofNew York, have invented certain new and useful Improvements in Magnets for Telegraphones, of which the follow-- ing is a full, clear, and exact descri )tion.

My invention relates to certain features of im rovement in electromagnets and particular y in the recordingand reproducing electromagnet of an ap )aratus for magnetically recording soundand speech. A well known example of a machine of. this type is the telegpresent invention is ap licable. n the telegraphone and similar apparatus, a steel disk,w1re or plate i's-contmuously moved in close proximity to the pole or oles of an electromagnet which is in a telep one circuit. The sound undulations of the telephone circuit are magnetically recorded on the steel by the changing magnetism of the electromagnet. It is necessary to have the plate moved in quite close proximity to, or in actual contact with, the pole piece to secure the best results, and it 1s evident that the pole piece is liable to be worn away by the friction unless special means are provided for avoiding this.

By the present invention I arrange to form the pole piece with aprotecti-ng armor or shield which receives substantially all the wear of.the frictional contact, but which does not in any way interfere with the magnetic and electrical functions ofthe mechanism. For this purpose-I preferto employ a hollow protectingcylinder of hard or wear resistive metalor material which surrounds the .pole

40 piece at the point of contact withthe steel recording and reproducing medium. 1

The invention further consists in the features of construction and combination hereinafter set forth and claimed.

. Fig. 5 is aform of the invention adapted for In the drawings: Figure 1 is a side view of the electromagnet and a recording andre use with steel wire as the recording and reproducing medium.

Referring to the drawings in which like parts are designated by the same reference sign, 1 indicates a disk or plate of hardened producing medium of the device.

' 2 is an electromagnet having a core 3, and a polar extension 4, which is of reduced diameter so as to concentrate the lines of force of the electromagnet into a very limited area of action on the steel medium 1.

5 denotes a protecting hollow cylinder of anti-friction or wear resistive metal or material, such as brass or a watch jewel. The central opening 6 of this protecting cylinder is of just suflicient size-to tightly it the polar extension 4, and when so placed the end surface of the cylinder and that of the pole 4 are flush. p

In use the medium 1 rotates or moves past the electromagnet 2, and the wear is for the most part received by the :larger surface of the anti-friction cylinder 5. In this way rapid wear on the pole piece is prevcnted'and it retains its original and proper form and condition.

- In Fig. 3 a slightly modified construction is shown which insures a better contact between the pole piece and the medium 1, in s ite of inequalities or foreign substances on the surface of said medium, since it does not present such a Wide base or area to rest on the moving plate. It will benoted that the cylinder 5 has two lateral faces 7 formed by beveling or cutting away, so that the face 8' stantially wider than the diameter of the olar extension 4. The length of the face 8 is, however, suflicient to provide adequate area for resisting the Wear. The long dimension of the face 8 should referably be in the direction of movement of the medium 1.

A further feature of the construction in Fig. 3 is that an additional polar extension 4 vis provided on the other end of the core 3, so that when one end becomes Worn the core may be equipped with a protecting or armor device 5, exactly similar to that at the other end ofthe'magn'et. .The two protecting devices are assembled with their elongated seen when the lower face is adjusted in line steel which constitutes the recording and rcofthe armor or protecting device is not submay be reversed to utilize the other. 'Th-is faces '8 extending; in the same direction. N In this way by observing the upper end it can be with the direction-of movement of the steel form, with a central hole or opening 10, to fit upon the polar extension 4. This construction gives a narrow zone or rin 11,'immedi ately around the edge of the po e to serve as an anti-friction or wear resistive surface.

In Fig. 5 a form of the invention is shown which is adapted for use with steel wire as a record recei or medium. The protecting piece is generally similar to the forms of Figs. 2 and 3, having a cylindrical body 5, and as shown a single bevel face 7, and a cen tral hole 6. There is, however, a groove 12 .diametrically cut'or formed across the face of the protecting piece, and which serves as a guide for the wire. In this way the wire is constrained to move in proper relation to the polar extension 4, and the heel of the cylinder taking the wear. The device 5, however, need not be beveled at all.

What I claim, is

1. In combination with the recording and reproducing medium of a telegraphone, an electromagnet having a pole piece adapted for contact with said medium continuously traveling tangentially past its face, said pole piece being provided with a wear resistive device.

2. In combination with the recording and reproducing medium of a telegraphone, anv

electromagnet having apole piece adapted for contact with said medium continuously traveling tangentially past its face, said pole piece having a wear resistive collar surrounding its extremity and flush with the end thereof.

3. In combination with the recording and reproducing medium of a telegraphone, an electromagnet having a pole piece with a reduced polar extension, said extension being provided with a wear resistive device.

4. In combination with the recording and reproducing medium of a telegraphone, an electromagnet having a pole piece adapted for contact with said medium continuously traveling tangentially past its face, said pole piece having a wear resistive device having a contact surface flush with the end surface thereof.

5. In combination with the recording and reproducing medium of a telegraphone, an

electromagnet having a pole piece adapted for contact with said medium continuously traveling tangentially pastits face, piece having a wear resistive device fixed thereto and flush with the end surface thereof.

6. In combination with the recording and reproducing medium of a telegraphone, an electromagnet having a reduced p0 ar extension adapted for contact with said medium said pole sound, comprising a core having a hollow,

wear resistive device surrounding its pole, two sides of said device being beveled or cut away reducing the width of the device to substantially the diameter of the pole.

9. An electromagnet for instruments for magnetically recording and reproducing sound,'c omprising a core having two polar extensions and wear resistive devices surrounding each of said polar extensions, their end faces being flush with the ends of said extension.

10, An electromagnet for instruments for magnetically recording and reproducing sound, comprising a core having a wear resistive device on one pole thereof, said resistive device, being elongated on its wearing surface.

11. An electromagnet for instruments for magnetically recording and reproducing sound, comprising a core having a wear re sistive device on one pole thereof, said re sistive device being elongated on its wearing surface, and an indicator on the other end of said core by which said device isproperly positioned. 1

12. An electromagnet for'instruments for 'magnetically recording and reproducing sound, comprising a core having a wear resistive device surrounding each of its poles, the end faces of said resistive device surrounding each of its poles, the end faces of said resistive devices being flush with the ends of the pole, and each of said devices being elongated on its wearing surfacein the same direction, whereby one pole may be properly positioned for use by observing the other as an indicator.

'- 13. In combination with the recording and reproducing medium of a telegraphone, an

electromagnet having a pole cooperating with said medium, and a jewel associated with said pole, and constituting a wear-resistive devlce.

In witness whereof, I subscribe my signature, in the presence of two witnesses.

JOHN .A.

Witnesses:

WALDO M. CHAPIN,

MAY Bran. 

